There presently exist numerous programmable thermostats that will allow a user to set back the temperature set point during select periods to provide energy savings. However, programming such a thermostat typically requires the user to complete a complex series of steps to select the temperatures and time periods before the user can initiate the set back program, or force the user to use a default program that does not ideally meet the users schedule. As a result, such thermostat programs aren""t utilized by many consumers. This problem of programming a thermostat is described in U. S. Pat. No. 5,782,296 to Mehta. Mehta describes a need for a user-friendly thermostat that operates as a manual thermostat at power-up, enabling the user to manually select a desired temperature immediately without having to spend time and effort programming the thermostat. It also describes a need for a thermostat that enables users to more easily customize or xe2x80x9cprogramxe2x80x9d their thermostats, as compared to existing xe2x80x9cpre-programmedxe2x80x9d thermostats. The thermostat in Mehta provides the user with an xe2x80x9cAuto Progxe2x80x9d button that the user can press repeatedly to select from one of several arbitrary pre-programmed sets of times and temperatures, of which may not be based on any supporting consumer data. This requires the user to scroll through the pre-programmed sets to find one with a temperature setting and schedule that are satisfactory to the user. Mehta does not, as such, address the need of many users who do not want to program a thermostat, but rather want to press a single button one time to run a single energy-saving set-back program that includes the user""s desired temperature setting. Thus, there is still a need for a thermostat that can be easily programmed to set back the user""s desired temperature setting for a predetermined time period, by simply pressing a single button once.
There is provided, in accordance with one aspect of the invention, a digital thermostat comprising up and down temperature adjustment buttons, an LCD display, and a button for automatically initiating a single set back program including the last xe2x80x9cdesiredxe2x80x9d temperature selected by the user of the thermostat. The digital thermostat allows the user to adjust the temperature set point to a desirable setting using the up and down temperature buttons, and to press a program button once at any time to initiate a single program that sets back the user""s desired temperature setting by a predetermined amount during setback time periods. In the preferred embodiment, the setback time period is predetermined to simplify user programming, and is based on the xe2x80x9cgo to bedxe2x80x9d and xe2x80x9cget up timesxe2x80x9d of U.S. Households published by the National Sleep Foundation.
It is thus an object of the invention to provide a thermostat that can easily be programmed by pressing a single button once, for initiating a single program that sets back the last selected temperature setting by a predetermined amount during predetermined setback time periods. In another embodiment of the invention, the thermostat simplifies programming by setting the time for the user.
It is a further object of the invention to provide a thermostat that can automatically set the current time and date, to allow a user to easily initiate a single set back program without having to set the current time and date. The thermostat automatically sets the current time and date using information broadcasted by station WWVB, which is operated by the National Institute of Standards and Technology. The thermostat displays the local time on an LCD.